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Make DataFlowGraph::insts public, but restricted (#5450)

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We have some operations defined on DataFlowGraph purely to work around borrow-checker issues with InstructionData and other data on DataFlowGraph. Part of the problem is that indexing the DFG directly hides the fact that we're only indexing the insts field of the DFG.

This PR makes the insts field of the DFG public, but wraps it in a newtype that only allows indexing. This means that the borrow checker is better able to tell when operations on memory held by the DFG won't conflict, which comes up frequently when mutating ValueLists held by InstructionData.
This commit is contained in:
Trevor Elliott
2022-12-16 10:46:09 -08:00
committed by GitHub
parent 6323b0f9f4
commit 25bf8e0e67
31 changed files with 182 additions and 178 deletions
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20
cranelift/codegen/src/simple_preopt.rs
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@@ -142,7 +142,7 @@ fn package_up_divrem_info(
/// Examine `inst` to see if it is a div or rem by a constant, and if so return the operands,
/// signedness, operation size and div-vs-rem-ness in a handy bundle.
fn get_div_info(inst: Inst, dfg: &DataFlowGraph) -> Option<DivRemByConstInfo> {
if let InstructionData::BinaryImm64 { opcode, arg, imm } = dfg[inst] {
if let InstructionData::BinaryImm64 { opcode, arg, imm } = dfg.insts[inst] {
let (is_signed, is_rem) = match opcode {
Opcode::UdivImm => (false, false),
Opcode::UremImm => (false, true),
@@ -478,7 +478,7 @@ enum BranchOrderKind {
/// layout-wise. The unconditional jump can then become a fallthrough.
fn branch_order(pos: &mut FuncCursor, cfg: &mut ControlFlowGraph, block: Block, inst: Inst) {
let (term_inst, term_inst_args, term_dest, cond_inst, cond_inst_args, cond_dest, kind) =
match pos.func.dfg[inst] {
match pos.func.dfg.insts[inst] {
InstructionData::Jump {
opcode: Opcode::Jump,
destination,
@@ -500,7 +500,7 @@ fn branch_order(pos: &mut FuncCursor, cfg: &mut ControlFlowGraph, block: Block,
return;
};
let prev_inst_data = &pos.func.dfg[prev_inst];
let prev_inst_data = &pos.func.dfg.insts[prev_inst];
if let Some(prev_dest) = prev_inst_data.branch_destination() {
if prev_dest != next_block {
@@ -609,7 +609,7 @@ mod simplify {
if let InstructionData::UnaryImm {
opcode: Opcode::Iconst,
imm,
} = dfg[candidate_inst]
} = dfg.insts[candidate_inst]
{
return Some(imm);
}
@@ -631,7 +631,7 @@ mod simplify {
opcode: Opcode::IshlImm,
arg: prev_arg,
imm: prev_imm,
} = &pos.func.dfg[arg_inst]
} = &pos.func.dfg.insts[arg_inst]
{
if imm != *prev_imm {
return false;
@@ -677,7 +677,7 @@ mod simplify {
/// would likely be expanded back into an instruction on smaller types with the same initial
/// opcode, creating unnecessary churn.
fn simplify(pos: &mut FuncCursor, inst: Inst, native_word_width: u32) {
match pos.func.dfg[inst] {
match pos.func.dfg.insts[inst] {
InstructionData::Binary { opcode, args } => {
if let Some(mut imm) = resolve_imm64_value(&pos.func.dfg, args[1]) {
let new_opcode = match opcode {
@@ -748,7 +748,7 @@ mod simplify {
opcode: prev_opcode,
arg: prev_arg,
imm: prev_imm,
} = &pos.func.dfg[arg_inst]
} = &pos.func.dfg.insts[arg_inst]
{
if opcode == *prev_opcode
&& ty == pos.func.dfg.ctrl_typevar(arg_inst)
@@ -846,7 +846,7 @@ mod simplify {
opcode: br_opcode,
args: ref br_args,
..
} = pos.func.dfg[inst]
} = pos.func.dfg.insts[inst]
{
let first_arg = {
let args = pos.func.dfg.inst_args(inst);
@@ -865,7 +865,7 @@ mod simplify {
arg: cmp_arg,
cond: cmp_cond,
imm: cmp_imm,
} = pos.func.dfg[icmp_inst]
} = pos.func.dfg.insts[icmp_inst]
{
let cmp_imm: i64 = cmp_imm.into();
if cmp_imm != 0 {
@@ -900,7 +900,7 @@ mod simplify {
};
info.args.as_mut_slice(&mut pos.func.dfg.value_lists)[0] = info.cmp_arg;
if let InstructionData::Branch { ref mut opcode, .. } = pos.func.dfg[info.br_inst] {
if let InstructionData::Branch { ref mut opcode, .. } = pos.func.dfg.insts[info.br_inst] {
*opcode = info.new_opcode;
} else {
panic!();